Ammonium Chloride → tert-Butyl[6-chloro-3-(trifluoroacetyl)pyridin-2-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

8 g (35 mmol) of tert-butyl (6-chloropyridin-2-yl)carbamate (Example 105A) are introduced into 100 ml of THF and cooled to −50° C. 55 ml (87 mmol) of butyllithium (1.6N) are added dropwise. After the dropwise addition is complete, the reaction is slowly warmed to −10° C. and kept at 0° C. for 2 h. It is then cooled again to −40° C., and 12.8 g (70 mmol) of 4-(trifluoroacetyl)morpholine (Example 35A), dissolved in 4 ml of THF, are added. The reaction solution is stirred at −40° C. for 1 h and then, at −40° C., poured into 1 l of ethyl acetate and 350 ml of ammonium chloride solution and extracted. The organic phase is separated off, dried over magnesium sulphate and concentrated in a rotary evaporator. The reaction mixture is chromatographed on silica gel (mobile phase cyclohexane/ethyl acetate 10:1). 9 g (79% of theory) of the product are obtained as an oil.

Provenance & Evidence